Process of making master records



Nov. 5, 1929, w. w. MCLAREN 1334339 PROCESS OF MAKING MASTER RECQRDS Filed April 4, 192'? UNITED STATES PATENT OFFICE WILLIAM WIMCLAREN, OF BIRMINGHAM, ALABA MA PROCESS OF MAKIN G MASTER RECORDS Application filed April 4, 1927. Serial No. 180,805.

This invention aims to provide a novel process for producing a master talking machine recordand, especially, to provide a novel process for hardening master records,

In the drawings Figure 1 shows in plan, a master phonograph record, in position to be hardened by the process hereinafter described;

Figure 2 is a cross section of the structure shown in Figure 1.

The numeral 1 denotes a master record,

I adapted to be used for the making of talking machine records of the disk type, although,

in practice, the method maybe used in connection with master records for making talking machines of any desired kind.

After the selection has been recorded on the record 1, the record is hardened by cooling the record, and by cooling it to a temperature below that of the surrounding air, the record being subjected to the action of a refrigerant, liquid air being suggested.

If desired, after the selection has been recorded on the record 1, as shown at 2, the, record may be placed upon a suitable support 3. There is a cavity 4 in the record, and in this cavity, the liquid air or other refrigerant is placed, as shown at 5.

The temperature of the record is lowered,

and the record is hardened, the record being made of any of the materials now employed for that purpose.

Although the hardening of the record lasts for a short 'time only, ordinarily, the advantages to be gained are that immediate re sults are produced, the master record being hardened so as to bring about a faithful reproduction or copy of the selection that has been recorded.

I What is claimed is A method of hardening a master record in the talking machine art, the method comprising retaining a refrigerant temporarily in an open cavity in the record.

In testimony that I claim the foregoing as my own, I have hereto aflixed my signature.

WILLIAM W. MCLAREN. 

